This invention relates to apparatus for auditory diagnosis and, more particularly, to new and improved audiometer apparatus utilizing electrical stimulation which is capable of providing very accurate diagnostic information about the hearing of a patient in a simple and highly effective manner.
It has long been known that the sensation of hearing can be created by stimulating a patient electrically by an audio modulated carrier signal of ultrasonic frequency applied through electrodes in contact with the skin in the region of the facial nerve system. The prior U.S. Pat. Nos. 3,563,246 and 3,586,791 disclose systems of this general character for stimulating hearing in hearing-deficient persons, in which LC series resonant coupling at carrier frequency is maintained between a signal source and the human subject so as to minimize the effect of changes in the impedance of the latter on the resonant frequency and to maximize the transfer of effective auditory information to the subject.
It is an object of the invention to provide new and improved audiometer apparatus, based on the electrical stimulation principles taught in the foregoing patents, which is capable of improved control of biotransduced energy, stability and precision.